500 Ricambi are Dutch, and use a lot of Polish parts, as do Axel Gerstl.
If you are buying Polish parts, then buy them from 126fan as they are the same, and much cheaper.
J Turas are Polish, and you can't gaurentee the quality or place of manufacture.
I would personally not touch any panels to restore an early Italian car unless you are sure they come from Italy or are Italian repro. Learn from my expensive mistakes! Its really not worth the risk. If you buy cheap and they don't fit, then it will cost more anyway. Better off going for the Italian stuff from the beginning.
If you are restoring a Polish car, or later model it wont matter.
Tom